N. H. SWELLENGREBEL AND C. STRICKLAND 
107 
really belonging to the life-cycle of T. lewisi, but these are exactly the 
forms concerning which Swingle has pronounced his doubts as to their 
systematic affinities. 
To summarise, we consider that Swingle has created an artificial 
life-cycle for T. lewisi in the flea. We do not question the existence 
of the Herpetomonad forms which he lias described, but we deny that he 
has established their specific identity as H. pattoni. 
REFERENCES. 
Swellbngrebel, N. H. and STRiCKiiANU, C. (1910). The development of Trypano¬ 
soma lewisi outside the vertebrate host. Parasitology, iii. .360. 
Swingle, L. (1911). The transmission of Trypanosoma lewisi \>y etc. Journ. 
of Infect. Diseases, viii. 125. 
